Chapter 6:
Thermal Energy
Practice Test
1.
How much energy is needed to heat 1 kg of sand, which has a specific heat of 664 J/(kg K) from 30°C to 50°C?
a.
33.2 J
b.
33,200 J
c.
13,280 J
d.
19,920 J
Hint
2.
In the morning, a concrete statue (specific heat = 600 J/(kg K)) has a temperature of 15°C. During the day, it sits in the sun and warms up to 40°C, gaining 90,000 J of thermal energy. What is its mass?
a.
6 kg
b.
3 kg
c.
2 kg
d.
1 kg
Hint
3.
To remove 800 J of heat from a refrigerator, the compressor in the refrigerator does 500 J of work. How much heat is released into the surrounding room?
a.
800 J
b.
300 J
c.
500 J
d.
1300 J
Hint
4.
A glass of water has temperature of 70°C. What is its temperature in Kelvin?
a.
300 K
b.
203 K
c.
343 K
d.
-70 K
Hint
5.
1 kg of water (specific heat = 4184 J/(kg K)) is heated from freezing (0°C) to boiling (100°C). What is the change in thermal energy?
a.
41,840 J
b.
418,400 J
c.
418.4 J
d.
4184 J
Hint
6.
The temperature of a block of iron, which has a specific heat of 450 J/(kg K), increases by 3 K when 2700 J of energy are added to it. What is the mass of this block of iron?
a.
3 kg
b.
6 kg
c.
1 kg
d.
2 kg
Hint
7.
Air is cooled from room temperature (25°C) to 100 K. What is the temperature difference in K?
a.
125 K
b.
75 K
c.
298 K
d.
198 K
Hint
8.
Water has a specific heat of 4184 J/(kg K). How much energy is needed to heat a kilogram of water 5°C?
a.
836.8 J
b.
4184 J
c.
20,920 J
d.
8368 J
Hint
9.
A calorimeter contains 1 kg of water (specific heat = 4184 J/(kg K)). An object with a mass of 4.23 kg is added to the water. If the water temperature increases by 3 K and the temperature of the object decreases by 1 K, what is the specific heat of the object?
a.
330 J/(kg K)
b.
53,095 J/(kg K)
c.
2967 J/(kg K)
d.
989 J/(kg K)
Hint
10.
A substance with a mass of 10 kg gains 106.5 kJ of heat when its temperature increases 15°C. What is this substance's specific heat?
a.
664 J/(kg K)
b.
450 J/(kg K)
c.
4184 J/(kg K)
d.
710 J/(kg K)
Hint
